1. Field of the Invention
The present invention relates to a feeding system for strip material for transporting a strip over a conveying distance of limited length, particularly in treatment plants for metal strip.
2. Description of the Related Art
A feeding system of the above-described type can best be explained with the aid of pickling lines for metal strip. Pickling plants which have been built in the past are of three different types:
a) pusher-type pickling plants for productions of about 300,000 tons/year;
b) semi-continuous pickling plants for productions of about 500,000 tons/year; and
c) continuous pickling plants for productions of up to 2,300,000 tons/year.
A comparison of the three types of pickling plants shows that the semi-continuous pickling plant and the continuous pickling plant operate in accordance with the same system, i.e., they utilize an endless belt. They only differ from each other with respect to the more-or-less complicated mechanical devices for bridging the idle periods during entry and exit, such as during coil exchange and welding.
In the pusher-type pickling plant, each strip is newly inserted and a pulling force is applied only after three windings of the strip beginning have been wound onto the coiler and the plant is subsequently accelerated to pickling speed. The particularly simple machine equipment of the pusher-type pickling plant (the plant includes only an uncoiler, a straightening machine, a pickling part, transverse cutting shears and a coiler) has been the reason that it was frequently attempted to increase the efficiency by increasing the inserting speed and by providing additional guide systems. In thin strips having an approximate strip thickness of below 2.5 mm, additional difficulties occur if such non-stiff strips are to be advanced over the necessary distance. For the above reasons, the pusher-type pickling plant has not been used very often.
It is, therefore, the primary object of the present invention to provide a feeding system for strip material which can be used equally for thin and thick strips and, when used in pickling plants, are equivalent in operation to a continuous pickling plant, even though the supply of strip is discontinuous, as is the case in a pusher-type pickling plant.